Tracking microstructural adaptations in primary visual areas: A diffusion kurtosis imaging study on visuomotor learning

This study investigates the potential of Diffusion Kurtosis Imaging (DKI) to detect microstructural changes induced by visuomotor training and its added value over Diffusion Tensor Imaging (DTI). Fourteen healthy participants completed a six-week home-based eye movement training intervention. Pre-and post-training DKI scans were analysed. Descriptive analysis, including the Coefficient of Variation (CV) and Bland-Altman (BA) metrics, was used to assess training effects. Results revealed significant reductions in kurtosis (MK, RK, AK) and diffusivity (MD) in task-relevant areas, particularly the cuneus, with overlapping findings between DKI and DTI-derived measures. In contrast, the pericalcarine area showed reductions only in MK and AK, suggesting that kurtosis metrics were more sensitive in this region. Increases in KA and FA post-training were not significant. BA analysis confirmed systematic training-related changes in the visual target area, while the transverse temporal gyrus, used as a control, remained stable, providing evidence for the specificity of these effects. These findings highlight DKI's ability to capture training-induced microstructural changes, complementing DTI. Among the metrics, AK emerged as a stable, sensitive marker, while MK and RK provided additional insights with greater variability. This study underscores the role of the cuneus in visuomotor adaptation and the potential of DKI to measure microstructural change cognitive training and neurorehabilitation.